Catalysts, which exist as a separate phase from the reactants and/or reaction product mixtures have generally been supported on inorganic particles or carbon fibers. These support materials lack flexibility and durability. Often times the nature of the support material dictates the geometry of the reactor and the service life of the catalyst.
Catalysts having inorganic supports are often heavy and awkward to deal with. They are generally in the form of small particles and have associated dust and fines. Such catalysts are often brittle or may become brittle in use; they may fracture or crumble causing increases in pressure drop or decreases in through-put of the chemical reaction that they are designed to facilitate. The support particles, and therefore, the catalyst, may shrink in service.
Catalysts on particulate supports generally require long times for charging into and discharging out of the reactors. The weight and the brittleness of the support also contributes to relatively long reductions or activation times once the catalyst is installed in the reactor. Because of the nature of the inorganic particulate catalyst support, once a reactor is charged, it may have to operate for some period of time, even at marginal rates, before a change out of catalyst is economical.
Resins have been used in some catalyst applications. For example, Japanese Patent Publication (Kokai) 55(1980)-149355 teaches the use of a heat resistant resin in a self-cleaning liner for microwave ovens. The resin's function is as a binder layer between oxidation catalyst particles and the support structure. The resin is not used as the catalyst support.
Japanese Patent Publication (Kokai) 56-118743 teaches a catalyst material for use in the water-hydrogen isotropic substitution reaction where the catalyst is packed into a porous bag. The bag is constructed from a fabric or a net. The fabric or net simply houses the catalyst and is not a catalyst support.
Japanese Patent Publication (Kokoku) 61-21206 teaches a catalyst of palladium supported on m-aramid polymer particles for use in dehydrohalogenation reactions. The polymer particles are required to be a m-aramid wherein the main constituent unit is m-phenylene isophthalamide.
Japanese Patent publication (Kokai) 7-47287 (1995) teaches a catalytic paper containing 5 to 30% fiber pulp, 5 to 15% glass fibers, 5 to 30% sepiolite and 30 to 85% catalyst material. This paper catalyst system requires the presence of sepiolite and large concentrations of catalyst material for activity.
U.S. Pat. No. 5,223,550 teaches a method for making a polybenzimidazole-containing fine particles. These particles are suggested as a possible catalyst support.